British police inspectors have been building a massive, secret database containing personal information on thousands of otherwise innocent political activists, an investigative report revealed Sunday.

"The hidden apparatus has been constructed to monitor 'domestic extremists', the Guardian can reveal in the first of a three-day series into the policing of protests. Detailed information about the political activities of campaigners is being stored on a number of overlapping IT systems, even if they have not committed a crime."

The UK paper added that the term "domestic extremist" has no legal basis, but is instead intended to tar those who may have participated in something so benign as civil disobedience.

Even merely attending a protest and standing on the outskirts of the crowd can be enough to land one on the National Public Order Intelligence Unit's list of "domestic extremists."